The invention generally relates to manual exercisers suitable for physical fitness, rehabilitation and athletic training and conditioning for cardiovascular endurance or strength development, and more particularly to an adjustable variable resistance exerciser to be operated by moving two pedals and cam levers against a resistance.
Mechanization of unprecedented proportions has sharply reduced the need for an expenditure of physical energy in daily living and the production of goods and services in contemporary society. The resultant lack of activity in an affluent society has increased obesity problems coupled with rising dangers in cardiovascular health and the ability of many persons to carry out normal daily tasks efficiently and safely. While most inventions aim at labor-saving and the conservation of human energy expenditures, the present invention is designed to provide a work media capable of creating a desired training and rehabilitation effect with convenience, economy and safety.
Fortunately, to remediate many of the physical fitness and rehabilitation problems, various forms of exercisers and regimens have been contrived, designed and developed to improve endurance, strength and cardiovascular function. In many situations existing training machines and methods are adequate, however, there are instances where this is not true. These are problem as illustrated by the following examples; training by jogging can be traumatic for many persons who are elderly or who have cardiovascular problems, jogging can also be inconvenient during foul weather or when on a trip where facilities are not available, exercise treadmills are cumbersome and produce much of the same trauma as jogging without a treadmill, bicycle ergometers are cumbersome and produce trauma in particular at the crotch of elderly persons, a jogging trampoline is ballistic in nature and does not provide an economical training effect, the local health club is often expensive and inconvenient, and so on. The above and other problems encountered during an extensive project on the biomechanical and physiological considerations of elderly participation in physical activity lead to the development of new training methods, which culminated in the present invention of the adjustable variable resistance exerciser.
The basic assumptions and guidelines for the present invention were to develop a machine which would be: (a) for large muscle involvement, such as the legs, arms, and body, (b) variable in resistance and such that the work performed on the invention can be either isokinetic or isotonic in nature, (c) easily adjustable for resistance changes, (d) safe to operate, (e) capable of producing a training effect for strength endurance and cardiovascular condition maintenance or improvement, (f) of a biomechically sound design, compatible with the mechanical movements of the human body, (g) portable for trips, (h) light in weight, and (i) inexpensive to manufacture. With the above guidelines in mind several prototypes of the adjustable variable resistance exerciser were extensively tested using biomechanical and work physiology laboratory procedures and where necessary the invention was modified to its present state.
The present invention, as an adjustable variable resistance exerciser, is new and constitutes an overall improvement on machines designed for use by the legs and arms for strength, endurance and cardiovascular training and conditioning. There is research evidence that the isokinectic nature of the present invention can produce a training effect over a greater range of movement than isometric procedures and the desired training effect can be reached over a shorter period of time than with isotonic procedures alone. Further, by adjusting the resistance on the present invention, the training effect can be localized for strength training, by increasing the resistance, or adjusted for endurance training, by decreasing the resistance. Also, the work can be performed at an aerobic or anaerobic rate. In addition, the isokinetic nature of the invention lends itself to tauma free work, for rehabilitation and the elderly, since even the highest resistance exerciser can be worked at mild work levels when the cadence is kept low.